Container cover and method of forming same



Ju 1965 N. F. MENGELKOCH CONTAINER COVER AND METHOD OF FORMING SAME Filed D60. 5, 1962 INVENTOR. A/flABfRT Hun 0s 4464 63/06 United States Patent'fO American Can Company, New York, N.Y., a corpora tion of New Jersey Filed Dec. 3, 1962, Ser. No. 241,826 4 Claims. (Cl. 113--121) This invention relates to sheet metal reclosure covers for containers and has particular reference to a novel method of forming locking projections onsuch covers.

Many of the tearing strip containers in use today are provided with a top end member which serves as a reclosure after the container has been opened. Usually the reclosure is formed witha vertical friction wall which makes a loose friction lit with the inwardly curled upper edge of an interior collar which is provided as a part of the container, and in order to prevent inadvertent unseating of the reclosure, this friction wall is provided with outwardly extending lugs which snap beneath the collar curl. These lugs are quite small, but must be comparatively deep and sharp in order to provide forasecure locking engagement between the end and collar'curl to prevent inadvertent dislodgment of the reclosure.

Heretofore, these lugs have usually been formed by small lugging dies which impress the lugs outwardly from the friction wall of the reclosure after the wall hasbeen formed by the end forming dies. Thus, both the radial and axial dimensions of these lugs are quite limited, lest the once drawn friction wall be torn by the lugging dies during the second drawing operation which produces the lugs. Further, the small lugging dies are difficult to maintain.

The present invention contemplates a novel method of producing the lugs which comprises the steps of forming a pluralityof vertical ribs in the friction wall of the reclosure cover during the cover forming operation, and then utilizing a rolling operation to iron out the major portion of the ribs,the unironed tips of the ribs which remain after the rolling operation comprising the improved locking lugs of the reclosure.

formed by parts of the regular cover forming dies which are comparatively large and sturdy and not unduly subject to breakage or rapid wear, the ribs are accurately dimen- Since the ribs are comparatively large with respect to the. lugs and are sioned, and since the dimensions of their tips are substantially unaffected by the rolling operation, this initial accuracy is reflected in the finished lugs.

Since the ribs are formed simultaneously with the cover drawing operation, the metal of the ribs is subjected to only a single drawing operation, and is much less susceptible to tearing. Further, the ribs can be initially drawn to protrudeaxially beyond the central panel of the cover, so that they extend more deeply into the container and engage beneath a deeper portion of the collar curl, thus providing a better locking action without requiring a deepening of the friction wall and aconsequent increase in the size of the cover blank.

An object of the invention therefore is the provision of a novel method of forming accurately dimensioned locking lugs on container covers.

Another object is the provision of a novel method of forming container reclosure locking lugs which project axially into the container beyond the bottom of the central panel of the reclosure, thus providing a more secure locking action at no increase in cost.

Still another object is the provision of a reclosure cover provided with locking lugs formed by the instant method invention.

Numerous other objects and advantages of the invention will be apparent as it is better understood from the Patented June 29,1965

following description, which, taken in connection with theaccompanying drawings, discloses a preferred embodiment thereof. I 6

Referring to the drawings:

FIGURE 1 is a vertical sectional view through a container having a reclosure cover provided with snap lugs made by the method of the present invention; 6

FIG. 2 is a fragmentary sectional view showing the first step of the instant method invention, the view also illustrating a portion of a die mechanism suitable for performing this step;

FIG. 3 is a fragmentary sectional view taken substantially along the line 33 of FIG. 2; FIG. 4 is a perspective view, on a reduced scale, of a reclosure cover at the completion of the first step of the instant method invention, the view showing the vertical ribs which are subsequently reshaped to form locking lugs;

FIG. 5 is a view similar to FIG. 2 illustrating the final step in the instant method of forming the locking lugs;

FIG. 6 is a viewsimilar to FIG. 3 takensubstantially along the line 66 in FIG. 5.; and

FIG. 7 is a fragmentary perspective view, on an enlarged scale, of a portion of the cover of FIG. 4 at the completion of the final step of the instant invention, the view including one of the completed locking lugs.

, As a preferred and exemplary embodiment of the invention, the drawings disclose a method of forming cover locking projections or snap lugs 11 on sheet metal covers or end members A of the type shown in FIG. 1 to provide for holding the cover A in place on a container body B when the cover A is used as a reclosure. Such reclosure covers are commonly used on interior collar cans of the general type shown in United States Letters Patent l,898,- 643, issued February 21, 1933, to John F. Peters on Interior Collar Can. In such cans a tearing strip 12 is set oif in the container body'wall 13 by a pair of score lines 14 to facilitate opening of the can and an interior collar C is secured in position within the container body wall 13 and is formed with a smooth inwardly curled top edge 15 to provide a seat or shoulder for the reclosure cover A. It will be realized, however, that the instant invention is not limited to use in the production of covers for use on (cans of this type, but is equally well adapted to produce locking lugson many other types of cans.

The reclosure cover A shown in FIG. 1, comprises a lower annular vertical friction side wall 16 which at its base 17 merges into a fiat countersunk central panel 18. At its upper edge the side wall 16 merges into an outwardly projecting substantially horizontal annular flat step 19. The outer edge of the step 19 merges into an upper vertical countersink wall 20 which at its upper edge merges'into a marginal flange zl. This latter flange 21 is utilized to permanently secure the'cover-A to the container body B 'by an iriterfolding of the flange 21 with a flange 22 formed atthe upper end of the container body to form a conven tional double seam 23 (see FIG. 1). As seen in FIG. 1, the cover wall '16preferably makes light frictional engagement with the inner portion of the collar curl 15.

In order to positively lock the reclosure cover A to the collar curl 15, a plurality of locking projections or snap lugs 11 are provided in the annular side wall 16, adjacent to or alongits base 17. These lugs 11 project radially beyond the wall 16 and extend beneath a portion of the inwardly extending collar curl 15 in snap-fit engagement therewith. The drawing shows five of these projections ,11 equally spaced around the periphery of the annular which is sufficiently tight to hold the cover in place, and yet not tight enough to prevent it from being easily removed when desired.

The cover A is formed from a flat piece of metal stock in a drawing operation by a suitable die forming mechanism, generally indicated by the letter M in FIGS. 2 and 3, which may be mounted in .a conventional punch press of the character disclosed in United States Letters Patent 2,136,933,.issued November 15, 1938, to E. A. Calleson on Manufacture of Sheet Metal Caps. In this die forming mechanism M,'the punch P comprises a center pad 24 and a pair of surrounding concentric, independently actuated, annular rings 25, 26. The die D comprises a center pad 27 and a pair of surrounding, independently actuated concentric annular rings 28, 29. Since a die mechanism of, this type is quite conventional, the means for actuating the various components of the punch P and die D are not shown in the drawings. However, reference is made to Uni-ted States Letters Patent 2,973,735, issued March 7, 1961, to V. T. Grover on Apparatus for Producing Reclosure Container Covers for more detailed information regarding such actuating means.

In accordance with the instant invention, a plurality of radially projecting, vertical ribs 30 are formed in the vertical friction wall 16 for substantially its full height simultaneously with the drawing of the cover A, there being one such rib 30 formed for each lug 11. finally desired. To effect the formation of the ribs 30, a plurality of elongated, easily replaceable inserts 32 formed with rib forming protuberances 33 are secured to the die pad 27, there being one insert 32 for each rib desired. As seen in FIGS. 2 and 3, the punch ring is correspondingly recessed to accommodate the inserts 32. The rib forming protuberances 33 project axially beyond the top of the die pad 27, and thus produce ribs which project axially beyond the cover panel 1 8. It will be noted from FIGS. 2 and 3 that the inserts 32 .are sturdy and substantial and not movable independently of the die pad 27. Thus, they are not subject to excess wear or misadjustment.

It is obvious that the ribs 30 are maintained under caretul control during the whole forming stroke of the die mechanism M, and can be very accurately dimensioned.

If desired, the rib forming protuberances 33 may be 7 formed directly in the'die pad .27 instead of in separate inserts 32.-

Following the formation of the ribs 30 as described, the cover flange 21 is curled as .at 34 (see FIG. 5) in any suitable manner and the cover A is then mounted on a circnlar rotating chuck 3-5 (see FIGS. 5 and 6) and the major portion of the ribs 30 ironed or rolled out by a rotating ironing roller 36 and forced back into the normal circular contour of the balance of the friction wall 16, leaving the unrolled tips of the ribs 30 projecting from the cover wall 16 and cover panel 18 to constitute the locking lugs '11.

Thisreshaping operation may be effected in any suitable manner, but preferably isdone in a conventional thread rolling machine wherein the chuck 35 is driven :and causes the cover A to rotate between the chuck 35 and roller 36, thus presenting the cover wall 16 to the roller 36 throughout its full circumference so that all of the ribs 30 are suitably ironed out. The chuck 35 preferably is slightly undersized with respect to the cover A so that thelatter can easilybe fed onto the chuck and removed from it.

. 4 As seen, the tips or unironed portions of the ribs 30 are not touched at all by the roller 36, and .are not reshaped by it. Thus, the original, accurate dimension of the ribs 30 in these unironed portions are retained, with the result that accurately dimensioned lugs 11 are provided in the cover 'wall' 16. In addition, because of the fact that the lugs 11 project axially beyond the center panel 18 of the cover A, the lugs 11 are enabled to engage against a deeper portion of the collar curl 15, thus providing an improved snap fit between the cover A .and collar C.' 'Asa result, the cover A provides a locking action equivalent to that provided by a cover having a deeper central panel and lugs which do not project beyond its central panel. This latter cover would, however, require a blank having a larger cutedge, and thus would cost more than the cover made by the method describedherein, so that substantial economies are made possible by the instant invention.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing description and it will be apparent that various changes may be made in the form,- construction, and arrangement of the parts and that changes may be made in the steps of the method described and their order of accomplishment without departing from the spirit and scopeof the invention' or sacrificing all of its material advantages, the form hereinbefore described being merely a preferred embodiment thereof.

I claim:

1. A method of forming a reclos ure cover, comprising forming a cover having an annular vertical side wall, simultaneously forming a plurality of ribs in said vertical side wall extending radially outward thereof, and ironing a portion of each of said ribs to the annular contour of said vertical wall while leaving an unironed portion of each of said ribs unironed to provide a cover locking lug.

2. The method of claim 1 wherein said ribs are formed to extend substantially the full height of said vertical side wall.

3. A method of forming a reclosure cover, comprising forming a cover having'a central countersunk panel and an annular vertical side wall surrounding said panel, simultaneously forming a plurality of radially projecting ribs in said sidewall for substantially'the full height thereof with the tips of said ribs projectingaxially beyond said central panel, and reforming the major portion of said ribs to the annular contour of said side wall while leaving the tips of said ribs unreformed to provide cover locking lugs.

4. The method of claim 3 wherein the effected by a roll forming operation.

reforming is References Cited by the Examiner UNITED STATES PATENTS 1,792,897 2/31 DeLacey 113121 2,209,416 7/40 Montelione 113121 2,288,349 6/42 Gibbs 1 l3121 2,868,410 1/59 Henchert 2206O 2,972,432 2/61 Flack et a1. 2206O CHARLES W. LANHAM, Primary Examiner.

DOUGLAS J. DRUMMOND, WILLIAM J. STEPHEN- SON, Examiners. 

1. A METHOD OF FORMING A RECLOSURE COVER, COMPRISING FORMING A COVER HAVING AN ANNULAR VERTICAL SIDE WALL, SIMULTANEOUSLY FORMING A PLURALITY OF RIBS IN SAID VERTICAL SIDE WALL EXTENDING RADIALLY OUTWARD THEREOF, AND IRONING A PORTION OF EACH OF SAID RIBS TO THE ANNULAR CONTOUR OF SAID VERTICAL WALL WHILE LEAVING AN UNIRONED PORTION OF EACH OF SAID RIBS UNIRONED TO PROVIDE A COVER LOCKING LUG. 